Process of assembling lasts



Fatented Mar. 15, 1927.

WALTER A. KRENTLER, OF DETROIT, MICHIGAN, ASSIGNOR T KRENTL'ER-ABNOLJS HINGE LAST COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

PROCESS OF ASSEMBLING LASTS.

Application filed. December In my present invention I have devised a novel and improved method of assembling two part lasts having connecting members, whereby the process of assembling automatically produces a relatively high degree of tension, uniting and holding the two last parts in constant engagement under the tension of the cutting members. In my copending application Ser. No. 7 45,364, I have illustrated and claimed broadly a type of accordion spring having laterally extending 'convolutions or a convolution to provide the spring feature, which, united with great strength, enables the forepart and heel part of the last to be connected by a single member and in an extremely compact form and under substantially the same constant tension at all times. 7

Referring to the drawings, illustrating a preferred embodiment of my invention,

Fig. 1 is a side view partly in cross-section of the completed last embodying my invention- Fig. 2 is a fragmentary side view also partly in cross-section, showing the last in collapsed position;

Fig. 3 is a fragmentary cross-sectional longitudinal view; and r Fig. 4 is a similar longitudinal cross-sectional view showing the method of assembling and uniting the last parts and putting them under the desired tension.

As shown in the drawings, a last with the heel part 2 and forepart 1 is divided along the usual lines of cut showing the upper faces 3 and 4, curved line of cut 5 and bottom shoulders 6 and 7. Bored recesses 7 and 8 respectively for the pins 9 in the forepart and 10 in the rearpart are also provided at proper spacings. The connecting member herein illustrated is that shown, described and claimed in my prior and copending application Ser. No. 7 45,364, and copending case Ser. No. 745,364, filed October 23, 1924, wherein I utilize an accordion spring 12, preferably with the attachment of the dutchman 14, and with the recesses at each end to receive the pins 9 and 10. This spring 12 and dutchman are preferably of appropriate width to snugly fill the sawed recesses 15 and 16 in the forepart and heel 8, 1925. Serial N0. 74,165.

part respectively, and the spring 12 has an end flat bearing portion'20, preferably atthe heel end, to give a broad bearing surface on the heel pin 10 and also to permit the assembling feature, which automatically puts the entire last parts and connecting hinge members under the desired tension.

As shown in Fig. 4, the member 12 and the recesses 7 and 8, are so proportioned, that the spacing of the recesses 7 and 8 and the corresponding rivets or pins 9 and 10, will be of sufficiently greater width than the normal length of the spring 12 with the recesses for said pins, so that the assembling of the last parts will produce the desired degree of tension. Thus in assembling the last I prefer to first fit the spring 12 into the forepart 1, and apply the pin 9, driving same through the forward bored opening in the spring 12. Thereupon I apply the heel part, in proper alinement, and then provide the special form of heel pin 10, having the conical point 21. This conical point is driven in against the edge of the upturned portion 20 of the spring 12, which, as clearly shown in Fig. 4 will be lengthened or sprung as the pin 10 is driven across the recess 16, picking up the tension of the entire spring member 12, and end 20, and thus initiating the tightening tension of the member 12 upon the last parts 1 and 2, as the rivet 10 is driven home, thereby uniting the last parts and spring, automatically putting the same under the desired tightening tension and completing the assembling of the last.

By my present invention I am thus enabled to predetermine, with great accuracy, the tension and strength of the connecting hinge member 12 or equivalent, uniting the forepart and heel part, while simultaneously I last part, proportioning vthe said single spring member and the connecting pin positions to predetermine the extent of resiliency applied to the spring and last members when completely assembled, then providing a-coni- Cally pointed pin, driving the same so that said conical point will first engagethe said extending portion of the spring, and completing the assembling and spring tension of the last parts by continuing the driving 10 action of the retaining pin- In testimony whereof, i have signed my name to this specification.

WALTER A.'KRENTLER. 

